Landscaping tools and construction equipment intended to be removably attached to host vehicles for use include but are not limited to sweepers, mowers, blowers, rollers, cultivators, post hole diggers and drivers, compressors, trimmers and plows, including snowplows. Such articles of equipment, sometimes referred to generically as attachments, are usually attached to the front, side or rear of a host vehicle such as a truck or tractor, and supported in use by the host vehicle. Some implements require host vehicle motion as part of their primary functionality, such as sweepers, snowplows and lawn mower attachments. Others are supported during stationary primary functionality and transported between events of primary functionality, such as posthole digger and driver attachments that are moved from hole to hole during the course of the work. Many such implements incorporate by necessity the ability to be structurally or mechanically reconfigured during usage or between events of primary usage, either by manual or powered adjustment of some aspect of the implement, such as for position, orientation, size, or range of motion adjustments.
Manual adjustments are often inconvenient and sometimes difficult or strenuous undertakings, particularly if they require a dedicated operator or the host vehicle operator to move back and forth from the vehicle operator station to the attachment.
Vehicle powered implement adjustments, particularly with controls positioned for vehicle operator convenience, are common, such as for front mounted snow plows with lift and tilt functions powered through high pressure hydraulic hoses from an engine-driven hydraulic pump. Other such implements or attachments may use engine power directed to a rotary shaft output called a power take-off (PTO), or be electrically powered by electrical cables extending from the host vehicle electrical system. Mechanical adjustments on towed landscaping, construction or farming implements such as rakes, planters, harrows, tillers, and bailers, may be similarly powered or alternatively driven by a separate, on-board power source such as a diesel or gasoline engine. Controls for such equipment may be provided or extended to the host or towing vehicle operator by electrical cables or mechanical linkages extending from the implement to the vehicle.
It is known to have snow plow attachments vertically rotationally mounted by two points horizontally displaced on a special support frame or carriage permanently installed under the front of a host vehicle such that the plowblade can be lifted and lowered by a separate, vehicle-mounted, powered lifting mechanism. The most common form of lifting mechanism is a separate assembly from the removable plow assembly that is incorporated into or permanently installed on the host vehicle, often on a vertically extending portion of the special support frame, where only the actual plow assembly is removed from the host vehicle between plowing operations and reattached when needed.
The lift mechanism is commonly a hydraulic piston attached by its base to the truck frame or special support frame so as to operate a lever, the base of which is rotationally attached to the special support frame. The plow assembly is connected at the two vertically pivotal, horizontally displaced, attach points on the under carriage or special frame. The forward extending lifting end of the lift lever is attached by a chain to the plow assembly. Hydraulic pressure for the piston is supplied by a hydraulic pump which in turn is driven by either the host vehicle's engine or an electric motor powered by the vehicle's electrical system. There may be additional pistons on the plow assembly for altering the plow angle between left and right side plowing angles, or into a V shape for shedding plowed material to both sides of the vehicle path. Hoses to these pistons are required to be connected to the host vehicle hydraulic pump system each time the plow is attached, and disconnected for removing the plow.
Operator controls for the lift mechanism are generally permanently installed on the host vehicle. This usually requires some modification of the vehicle to accommodate the required cables and control panel. The permanent installation of the special two-point mounting support frame and lift mechanism, and the control system, is usually performed by a professional at considerable cost. Removing and reinstalling these permanent components on another vehicle is problematic, so the plow system is dedicated to and limited to use with a particular host vehicle.
To that end, plowing implements have been developed that can be easily attached to the rear of any suitable vehicle, by use of a simple, one point attachment to a frame mounted box receiver with which many vehicles are fitted as original equipment or added for other reasons such as towing trailers. Box receivers are primarily designed for accepting a trailer hitch for towing trailers, and as such are securely attached to the vehicle frame for strength and rigidity, and are able to support a rear mounted snow plow. Simple plow mechanisms that provide for self alignment to the left or right side plowing angles as they are pulled, require no external power to adjust in that respect. Manually operated lift mechanisms, or linkages extending to the host vehicle have been used for lifting the plowblade of such implements.
Vehicles equipped with box receivers for pulling trailers as are commonly further equipped with an electrical connector through which trailer lights are connected in parallel with vehicle lights, for example tail lights, turn signals and brake lights. These vehicle lighting circuits are normally limited in their current requirements, and wired accordingly, and trailer light circuits connected to these host vehicle lighting circuits can not cumulatively draw more current than the design limits.
There has thus far not been offered a solution to the lift mechanism for a rear mounted plow that is as convenient as the front end permanent installation described above. A permanent installation of a lift mechanism on the back end of a vehicle is problematic, as important access to cargo space would be obstructed. The expense is significant, and the requirement for a dedicated vehicle is a further obstacle to convenience, flexibility of operations, and economy.